Optical Transport Network (OTN), as a core technology of the next generation transport network, has abundant Operation, Administration, and Maintenance (OAM) capabilities, enables the flexible scheduling and management of high-capacity services, and thus becomes a mainstream technology of the backbone transport network.
In signal transmission, an Ethernet needs to use an OTN to bear Ethernet signals, so as to achieve the high-capacity and long-distance transport of information. Considering the technology maturity and cost, the bearer capability of an OTN line is limited. When the bandwidth of a single OTN line is inadequate to bear Ethernet data traffic, virtual concatenation may be used to combine multiple OTN lines, so as to provide a higher bandwidth, and complete the data transport. For example, in an OTN with a bandwidth of 10 Gbps, a container of Optical Channel Payload Unit-2 (OPU2) grade may contain at most 10 Gbps of data information. If 40 Gbps of data needs to be transported, 4 containers of OPU2 grade are combined by using the virtual concatenation technology to form a 4 virtually concatenated OPU2s (OPU2-4V) container to bear the 40 Gbps bandwidth. The Ethernet data is encapsulated into 4 OPU2 containers which are individually added with corresponding virtual concatenation indication information, and then is carried in 4 independent Optical Channel Transport Unit-2 (OTU2) frames, so as to transport the data through 4 independent OTN lines. At a receiving end, the received 4 independent frames are de-framed to provide 4 OPU2 containers, and the 4 OPU2 containers are assembled to form an OPU2-4V container by identifying the virtual concatenation indication information, which is decapsulated to provide correct data.
Generally, the scheme that the OTN uses the virtual concatenation technology to bear Ethernet signals has the following requirements.
1. When partial line failure occurs to the OTN, the Ethernet needs to adjust the traffic correspondingly. For example, if a certain OTN line fails, the corresponding channel cannot correctly transmit data. In this case, an Ethernet equipment must decrease the data traffic to ensure the normal transmission of data. As the Ethernet data is transmitted though multiple channels in parallel, and the data among the channels is correlated to each other, after a part of the channels fail, other channels cannot combine and obtain the correct data, resulting in failure of the Ethernet data transmission. Accordingly, the Ethernet is required to decrease the traffic, so as to enable the signal to be transmitted on available channels.
2. When the data traffic of the Ethernet equipment is adjusted, the OTN needs to perform line adjustment correspondingly, so as to save OTN line resources.
FIG. 1 shows a solution of the prior art, and is a schematic view of the framework supporting OTN line capacity adjustment according to the prior art. As shown in FIG. 1, Ethernet data is processed by a receiving unit, and transferred to an encapsulation unit, which encapsulates Ethernet signals into a virtually concatenated container based on the rate grade, for example, encapsulates the signals into a virtually concatenated container according to the rate grade of OPU2. Then, the encapsulated data is framed to generate OTU format signals capable of being transmitted in an OTN line, optical signal conversion is performed on the OTU signals by an OTN line sending unit, and the signals are then transmitted in an optical fiber. In the prior art, through the interaction between a Link Capacity Adjust Scheme (LCAS) module and an encapsulation unit, a decapsulation unit, a virtual concatenation framing/de-framing unit, and an Ethernet line transceiver unit, the dynamic line adjustment and the partial line failure protection of the OTN may be achieved.
After the research on the prior art, the inventors find that in the prior art, the dynamic line adjustment and the partial line failure protection functions only become effective in the OTN, and cannot interact with an Ethernet equipment. When a part of the OTN line fails such that a corresponding channel becomes unavailable, the Ethernet equipment cannot be informed of the change in time to decrease data traffic, so that the multi-channel data cannot be combined to obtain correct data, resulting in the Ethernet data transmission failure. Moreover, when the Ethernet equipment traffic is adjusted, the OTN cannot carry out corresponding adjustment, for example, when Ethernet data traffic is decreased, the OTN still provides a large bandwidth, thereby causing resource waste.